Counter-rotatable booster compressor assembly for a gas turbine engine

A counter-rotatable booster compressor assembly (36) for a gas turbine engine (10) has a counter-rotatable fan section (12) with a first fan blade row (18) connected to a first drive shaft (46) and a second fan blade row (22) axially spaced from the first fan blade row (18) and connected to a second drive shaft (48). The counter-rotatable booster compressor assembly (36) includes a first compressor blade row (38) connected to the first drive shaft (46) and a second compressor blade row (40) interdigitated with the first compressor blade row (38) and connected to the second drive shaft (48). A portion of each fan blade (22) of the second fan blade row (22) extends through a flowpath (80) of the counter-rotatable booster compressor (36) so as to function as a compressor blade (104) in the second compressor blade row (40). The counter-rotatable booster compressor (36) further includes a first platform member (94) integral with each fan blade (22) of the second fan blade row (22) at a first location so as to form an inner flowpath for the counter-rotatable booster compressor (36) and a second platform member (96) integral with each fan blade (22) of the second fan blade row (22) at a second location so as to form an outer flowpath for the counter-rotatable booster compressor (36).